Process for making heavy-duty springs



Aprilzl, 1931. Y

llmm In" IIIII Patented Apr. 21, i931l y UNITED STATES PATENT oFElcE yEntrant-1s. BELL AND osc'ait` n. WIKANDER, or rITTsBURGH, PENNSYLVANTA; As-

srGNoRls To EncEw-.amnn STEEL COMPANY, or PITTSBURGH, lPENN.'sxmraivm, A

CORPORATION OF .PENNSYLVANIA PROCESS FOR MAKING HEAVY-DUTY SPRINGS Application led July 272,

-This invention relates in general to the manufacture of heavy duty springs and a method of sizing the ring, and more particularly to heavy duty springs constructed ofy inner and outer members alternately ar.- ranged and provided with bevelled interenaging faces operating through wedging action under compression of the spring to stretch and compress the material of the rings and a method of sizing the rings so that they will permanently retain a given form and will not sag under operating strains or the like. l E These springs rely upon the tensile strength i and compressive resistive strength for their spring action and this' strength is increased upon stretching or compressing the material. -It is a primary object of the present invention to provide a method of [stretching and compressing the material that will at the same time size the ring or form it to operating size after the spring elements have been fully formed and heat treated, to increase the strength and flexibility of the rings and to prevent sagging of the spring-in use.

Another important object of the invention is to provide a spring, the yielding movement of which is limited by the spring itself, and l that when the maximum yieldis reached the spring forms a substantially solid column for supporting the load, and thus prevents overloading or injury such as may be caused by undue strains.

Numerous otherobjects and advantages of the invention will be apparent as it is better i understood from the following description, which, taken in connection with the accompanying drawings, discloses apreferred embodiment thereof.

.Referring tothe drawings, Figure 1 is asection through a spring of the character above described; and i Figs. 2 and 3 are enlarged fragmentary sections showing the spring both free of andunder compression. p Our present invention does not relate to the/method of forming the spring elements. The spring is, however, constructed of outer solidl ring members 11 and inner solid ringumembers 12. The outer members are prodifferent result.

1926. Serial No. 124,163.

vided with internal bevelled or inclined faces 'i 1 3 and the inner members are -provided with companion bevelled or inclined faces 14. In v the present instance a pair of beveled faces is provided on each ring element and these meet in a circumferential line extendingabout the largest diameter ofthe internal elements and the smaller diameter of the external.

Our present invention has for its purpose the provision of a method of sizing springs or spring rings of this type, so that they will maintain a predetermined size throughout their period of service and to increase the elasticity or tensile strength of the ring.

4This is accomplished byforming the ring to a Size sli htly smaller than operating size and stretc ing the ring when assembled, preferably between suitable dies, a predetermined number of times, such as by assembling an entire spring or taking each ring unit separately and between dies formed in accordance withthe co-operating rings and applyp ing a pressure to the dies or spring that is in excess of the maximum spring power. This stretchin orl compressing the rings, move- 'ment of t e die is preferably limited so that an effect would be obtained similar to that which would'be obtained if the rings were stretched while assembled; that is, when under full compressionthe adjacent surfaces of the outer rings, the inner rings, or both the outer and inner rings will be in contact, this being the limit of the movement ofthe spring.

The pressure is applied until suliicient movement is obtainedv to cause a contact of the surfaces o'f adjacent rings at each application,` and it will be noted that when so applied during the irst application the ring or rings under treatment will be either stretched or compressed. During this rst stretchingor compression, however, the strain on the libres in the metal is not equal and by repeatedly applying a pressure the strain on the fibres 1n the metal is gradually equalized. This pressure should be repeatedly applied and released until the repetitions have amounted to some fifteen or twenty times, or until no more displacement of the fibres of the metal occurs, and the stretching or compressing of the metal is preferably carried to the extent of approximately one-third of one per cent. Since the strain of the ring and the strain on the fibres of the ring are equal or substantially so, when the ring is once stretched to size it will not sag under operating strains, as these are slightly less than the strain applied during the sizing process.

An important advantage fiowing from this operation is that the pressure thus applied fer a number of times bringing the inner rings into contact is greater than the force that the spring can receive in service. Stated differently, lnyimproved process provides a test for the springs that insures against breakage up to full compression. It will, of course, be manifest that any pressure that will accomplish the result is contemplated Within the spirit and scope of the invention.

` It is thought that the invention and manyl of its attendant advantages will be understood from the foregoing without further description and it will be manifest that the process selected in connection with the description of the preferred embodiment may be departed from in various ways without departing from the spirit and scope of the invention.

We claim:

1. The process of making springs, which `comprises providing a plurality of inner and outer solid rings adapted to e alternately arran ed in a spring assembly, and provided with eveled faces for interengagement in such assembly, arranging said rings with the beveled faces in engagement and ap iying pressure thereto in controlled amount lbr increasing the elastic limit of the material.

2. The process of making springs, which.

comprises providing a plurality of inner and c-uter solid rings adapted to be alternately arranged in a spring assembly, and provided with beveled faces for interengagement in such assembly, arranging said rings with the beveled faces in engagement and ap lying f' 2 pressure thereto under controlled con 'tions .such a for increasing the elastic limit of the niaterial.

4. The4 process of making springs, which beveled faces in engagement and repeatedly applying pressure thereto to increase the elastic limit of material.

6. The process of' making springs, which comprises providing a pluraliteof inner and outer solid rings adapted to alternately arranged in a spring assembly, and provided With beveled faces for interengagement in such assembly, arranging said rings with .the beveled faces in engagement and applying pressure thereto'until rings of said sprmg assembly are in contact atfaces other than said beveled faces, whereby the elastic l1m1t of the material is increased.

7. The process of making springs, which comprises providing a set of outer solid rings and a set of inner solid rings, the members .of said sets being adapted to be arranged to alternate with the members of the com anion set, and the members of both sets aving 'beveled faces for interengagement in assembly, and stretching the outer rings by presn sure applied under controlled conditions te increase the elastic limit of the material.

' 8. The process of making springs, which comprises providing a plurality of inner and outer solid rings adapted to be alternately arranged in a spring assembly, and provided with beveled faces for interengagement 1n such assembly,arranging said rings with the beveled faces in engagement and repeatedly applying pressure thereto and under controlled conditions, said pressure being 1n excess of that the spring will sustain in service, whereb to wear in and smooth the engaging faces o the ring.

9. The process of making springs, which comprises providing a plurality of inner and outer solid rings adapted to be alternately arran'A d in a spring assembly, and provided withl veled faces for interengagement in mbly, arranging said rings with the beveled yaces in engagement and repeatedly applying*` pressure thereto and under controlled conditions. Y

FRANK B. BELL. GSCAR R. WIKANDER. 

